Protected lock means for electrically-operated,hand-manipulated tools

ABSTRACT

A portable, hand-held electrically powered tool activated, during operation, by a trigger-type, handle-mounted switchoperator in a convenient position lending to efficient operation of the tool and in which the tool switch has at least an &#39;&#39;&#39;&#39;on&#39;&#39;&#39;&#39; and &#39;&#39;&#39;&#39;off&#39;&#39;&#39;&#39; position. A selectively operable lock means for the switch operator is accessible to the user of the tool but is recessed or protected so that it must be intentionally operated to a &#39;&#39;&#39;&#39;lock&#39;&#39;&#39;&#39; position. The lock means is constructed so that momentary reapplication of manual pressure to the switch-operator automatically de-activates the lock means and allows the electric motor to turn &#39;&#39;&#39;&#39;off&#39;&#39;&#39;&#39; upon release of pressure on the operator. The lock means is preferably, but not necessarily, located in a central position on the handle of the tool below the switchoperator. In addition, the switch-operator may have two or more &#39;&#39;&#39;&#39;on&#39;&#39;&#39;&#39; positions in which it may be locked.

United States Patent 1 1 Rosenthal, Jr. et a1.

1 1 PROTECTED LOCK MEANS FOR ELECTRICALLY-OPERATED,

1 HAND-MANIPULATED TOOLS [75] Inventors: Francis Joseph Rosenthal, Jr.,Fork;

Lewis Hampton Rohr, Baltimore, both of Md.

[73] Assignee: The Black and Decker Manufacturing Company, Towson, Md.

22 Filed: Jan. 3, 1973 1211 Appl. No.: 320,732

[52] us. or. 310/68 A, 200/169 PB 511 nt. c1. H02k-ll/00 158 Field ofSearch 310/67 R, 68 A; 200/157, 169 PB [56] References Cited UNITEDSTATES PATENTS 2,200,322 5/1940 Arnesen 200/157 X; 2,487,011 11/1949Wilhide 310/68 A X Dec. 25, 1973 Primary Examiner-James D. TrammellAssistant Examiner-l-larry E. Moose, Jr. Att0rney--Joseph R. Slotnik etal.

[5 7] ABSTRACT A portable, hand-held electrically powered toolactivated, during operation, by a trigger-type, handlemountedswitch-operator in a convenient position lending to efficient operationof the tool and in which the tool switch has at least an on and off"position. A selectively operable lock means for the switch operator isaccessible to the user of the tool but is recessed or protected so thatit must be intentionally operated to a lock" position. The lock means isconstructed so that momentary reapplication of manual pressure to theswitch-operator automatically de-activates the lock means and allows theelectric motor to turn off" upon release of pressure on the operator.The lock means is preferably, but not necessarily, located in a centralposition on the handle of the tool below the switch-operator. Inaddition, the switch-operator may have two or more on positions in whichit may be locked.

13 Claims, 5 Drawing Figures PROTECTED LOCK MEANS FORELECTRICALLY-OPERATED, HAND-MANIPULATED TOOLS BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relates generally toportable, handheld, electrically powered tools and the like, and moreparticularly to an improved switch-operator lock means therefore.

2. Description of Prior Art generally Electric power tools such asportable sanders, drills, circular saws and the like as well as otherportable, electric powered devices, often incorporate a switchoperator,for example, a trigger-like element on a handle, which can be locked inan on" poisition whereby the electric motor of the device continues tooperate without the user keeping the switch-operator depressed.Generally, the locked switch-operator is released by momentarily,manually depressing the switch-operator.conventionally, switch-operatorlocks have included means exposed at the surface of the handle or toolhousing, such as a button-like element projecting laterally from thehandle. These exposed locking means are subject to inadvertent oraccidental actuation such as by the user with his hand in normalposition on the handle, whereby the tool may accidentally be locked on.

SUMMARY OF THE INVENTION Thepresent invention is directed to an improvedswitch-operator lock means protectively disposed within a recess orprotecting portion of the tool handle or housing of an electricallyoperated power tool and the like. Thenovel construction is such thatnormal operation of the tool can'not result in the tool or device beinginadvertently or accidentally locked on but must be intentionally soactuated. The construction is such that the switch operator can belocked on" in more than one position, and is automatically released uponmomentary reapplication of pressure to the switchoperator'. Furthermore,the lock means desirably can be disposed for equal convenience for rightand left-hand users.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a powertool incorporating the invention; v

FIG. 2 is an enlarged fragmentary perspective view of the handle portionof the tool of FIG. 1 showing in phantom lines the handle gripped in ausers hand and illustrating the manner in which the other hand is used Ito manipulate and positively actuate the switchoperator lock means;

FIG. 3 is an enlarged fragmentary side elevation, with portions brokenaway showing the operative portion of the switchoperator in conjunctionwith the improved lock means, and showing in phantom lines the positionDESCRIPTION OF A PREFERRED EMBODIMENT Before referring to the drawing indetail, it will be understood that the housing switch, switch-operatorand- /or lock means may be constructed of a variety of suitablematerials. Further, although the switch-operator lock means of thepresent invention is illustrated in relation to a portable drill, thisexpedient may be incorporated on other portable electric powered toolssuch as sanders, circular saws, etc., as well as other portable electricdevices. Also, although the preferred embodiment discloses the powertool as being operated from a convention A. C. power source connectedthereto by a line cord, the present invention isequally applicable tocordless, battery-powered devices.

Referring to FIG. 1, a portable electric drill, in which the inventionfinds particular use, is indicated generally at 10 and comprises ahousing 12 enclosing an electric motor drivingly connected to a toolchuck 14. A dependent handle 16 is fixed to the housing 12 and has aline cord 18 extending therefrom and adapted for connection to aconventional A. C. source.

The tool 10 is provided with a control switch 20 suitably disposed inthe handle 16 and interconnected with the motor for control thereof inthe usual manner. The illustrated switch 20 embodies a housing 21 havinga switch operator or trigger 22 and a slider 26 rigid therewith slidablysupported in the housing 21 and normally biased toward an off position,or toward the left, as seen in FIGS. 3 and 4 by a spring within thehousing 21. Switches of this type are well known in the art, forexample, as shown in. the Matthews U.S. Pat. RE.26,267 issued Sept. 26,1967. Thus, to turn the tool 10 on," the user applies finger pressureto-the trigger 22 moving it toward the right. Normally, the tool 10 isturned off by releasing pressure on the trigger 22 whereupon it returnsto the left opening the switch 20.

The switch housing 21 has a guide sleeve 34 formed integral therewithand extending forwardly thereof. A

plunger 36 has an enlarged portion 38 vertically slidably disposed in abore 37 in the sleeve 34 and has an upper flared end 46 disposed outsideof the sleeve 34.

. A compression spring 42 within the sleeve 34 engages a shoulder 40 onthe plunger 38 and normally biases it downwardly as seen in the figures,toward the position shown in FIG. 3. Engagement between the flared end46 and the sleeve 34 limits this downward movement.

An actuator 32 is provided for the plunger 36 and includes a foot 42fixed to the enlarged portion 38, and a button 44 slidable on a face 34of sleeve 44. The button 44 extends partly into an aperture 30 formedinthe handle 16 below the trigger 22, and may be slid upwardly using onesindex finger as shown in FIG. 2. When the button 44 is so moved, afterthe trigger 22 has first been depressed using the index finger on onesother band, also as shown in FIG. 2, the flared plunger end 46 movesinto engagement with a boss 28 depending from trigger 22.

Specifically, the illustrated switch 20 is of the two spee "variety suchthat partial depression of trigger 22 effects low speed tool operation,while full trigger depression effects high speed operation. The boss 28has a pair of stepped shoulders 29, 31 adapted to align with plunger 36when the trigger 22 is partially and fully depressed, respectively.Thus, when it is desired to lock the tool 10 on for low speed operation,the trigger 22 is partially depressed and the button 44 raised (usingthe fingers in the manner shown in FIG. 2) to position whereby biasedengagement between shoulder'31 and plunger end 46 holds trigger 22 andplunger 36 in this position. When it is desired to turn the tool off,

the user applies momentary pressure to trigger 22'releasing shoulder 29(31) from plunger end 42, whereby plunger 36 returns to. the full lineposition shown in FIG. 3 under the force of spring 42. Thereafterrelease of pressure on trigger 22 allows it to return to the off"position. a

It will be appreciated that the guarded nature of button 44, shown hereby the button 44 being recessed within the wall of handle aperture 30,prevents the actuator 32 from being accidentally or unitentio'nallyactuated to a locking position, or when in locked engagement withtrigger boss 28 from being held in the locked position when it isdesired to turn the tool off. Thus, this undesirable condition, existingin prior art exposed locking buttons, is hereby eliminated. In otherwords, the lock actuator 32 of the present invention requires apositive, deliberate act to lock the switch andtool 10 on.

' Furthermore, the central disposition of the actuator 32 and of trigger22 lends the device to use with equal ease by right and left handedpersons.

- Also, the general concept of the invention is applicable to singlespeed and/or reversible devices as well as those embodying variablespeed switches. In the latter, boss 28 could be adjustable relative totrigger 22.

By the foregoing, there has been disclosed an improved switch controland lock means for electric powered devices such as power tools and thelike, the invention being illustrated and described in a preferred formand in a typical'environment. However, it will be understood thatvarious additions, substitutions, modifications and omissions may bemadeto this'form and environment without departure from the spirit of theinvention.

What is claimed is:

. 1. In hand-portable, manually-manipulated, electrically powered toolcomprising in combination housing means; electrically-operated motormeans in said housing means; means for supplying electrical power tosaid motor means; power-output means operatively connected to saidelectrically operated motor means, said housing means including handlemeans to gripped in a users hand when the tool is operated; switch meansoperativelyconnected to said motor means for activatmeans having amanually manipulated operator portion disposed in a recess in saidhandle,and spaced inwardly from the outer surface of said handle, saidoperator portion being accessible to finger engagement by a user,whereby the lock means require positive intentional actuation to bemoved to the position retaining the switch operator means on and isprevented from inadvertent or accidental activation during use of thetool. I

2. The structure as claimed in claim 1 in which said handle meansdepends from said housing, said switchoperator means comprising atrigger element projecting from said handle means in a convenient,normal position on said handle means whereby said operator means isoperable while conveniently gripped in a usershand through a normal,physical gripping action, said switch-operator means being normallyurged toward the off position and being depressible into said handlemeans to turn said tool on, said lock means including spring meansnormally urging-it toward aposition released from said trigger. I

3. The structure as claimed in claim 2 in which said switch-operatormeans includes a portion movable therewith and variably positionablerelative to said means for retaining the switch-operator in an onposition, movement lock means comprising a displaceable abutment elementoperatively engaged by said spring means, said displaceable abutmentelement being engagable with said portion movable, with saidswitchoperator and operable to prevent the switch-operator from movingto said off position.-

4. The structure claimed in claim 3 in which said switch-operator meanshas a path of movement in one direction, said displaceable abutmentincluding a terminal portion positionable in said path of mvoement ofsaid switch-operator means portion and engagable therewith and subjectto the force applied to said switch-operator normally urging it to saidoff position.

5. The structure as claimed in claim 4- in which said switch-operatorcomprises a finger-engagable portion exposed exteriorly of said handlemeans, said portion movable with said switch-operator means comprisingat least one'recess portion, said abutment portion being disp'laceablyengageable in said recess portion for retaining said switch-operatormeansiin a locked condition. U I

6. The structure as claimed in claim 4 in which said switch-operatormeans includes a recessed portion opening towards said abutment portion,said abutment portion being engagable in said recessed portion forlocking said switch-operator means in a relatively fixed positionsubject to release by manual depression of the switch-operator by theuser of the tool.

7. A motor housing for a portable, electrically powered tool includingan operator-held handle, switch means in said handle including-aspring-urged switchoperator element havinga portion accessibleexteriorly of said handle for. activating said tool, and lock meansportion movable relative to said lock means, said lock means including aspring-urged abutment element normally urging said lock means to an offposition.

9 The structure as claimed in claim 8 in which said switch-operatorcomprises a trigger-like element displaceable in a path of travelrelative to said handle, said orienting portion comprising at least onerecess opening toward said lock means, said lock rneans comprising anelongated displaceable abutment element retained in a path of movementsubstantially normal to the path of travel of said trigger-like element.

10. The structure as claimed in claim 9 in which said lock meanscomprises a sleeve circumposed about and guidingly engaging saidelongated element, spring means circumposed about said elongated elementand normally urging it away from said trigger-like element, the portionexposed at the surface of the handle of said lock means being fixedlyconnected to said elongated element. I

11. The structure as claimed in claim 7 in which said handle includes anopening into which an exposed portion of said lock means operatorelement projects, the outer surface of said handle at said opening beingspaced outwardly from and protecting the lock means operator elementfrom inadvertent engagement and actuation by a users hand.

12. The structure as claimed in claim 1 1 in which said handle dependsfrom one end of the housing, the switch-operator being disposed at anupper. inner portion of said handle, said operator element of said lockmeans being disposed immediately below said switchoperator.

13. A hand-held, portable, power-operated device comprising a housingenclosing a motor, output means interconnected with said motor anddriven thereby and located exteriorly of said housing, said housingincluding a handle portion for manipulation of said device, a motorcontrolling operator accessibly disposed on said handle portion foroperation by a user, means normally biasing said operator toward an offposition, and lock means for said motor controlling operator, said lockmeans including a finger engageable portion located in an opening insaid handle portion and spaced inwardly from the outer surface thereof,said lock means being releasably engageable with said motor controllingoperator and operable to lock said operator in said on posi-' tion,means normally biasing said lock means toward a position released fromsaid operator, whereby said lock means and said operator areinterconnectable when both are operator actuated against theirrespective biasing means, and are releasable to permit said operator tomove to its off position upon momentary reengagement of said operatormeans by said user.

UNETED STA'EE' PATENT OFFICE CEKEHTPCAEEZ i); CORRECTION Pete-m eetedDecember 1973 Inventot(s) Francis Josegh Rosenthal, Jr. and LewisHampton Rohr It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 17, "poisition" should be --position;

column 1, line 68, after the semicolon insert and-.

Column 2, line 50, change "face 34 of sleeve 44" to read front face ofsleeve 34.

Column 3, line 15, after "end" change "42" to 46; line 23,"unitentionally" should be unintentionally-; line 49 after "In" inserta-.

Column 4 line 25, "movement" should be said-; line 33, after "abutment"insert element--; line 34, "mvoement" should be -movement.

Signed and Scaled this sixteenth Day Of September 1975 [SEAL] A ttest:

RUTH C. MASON C. MARSHALL DANN Arresting Offic r (ummissimmr ofParenrsand Trademarks

1. In hand-portable, manually-manipulated, electrically powered toolcomprising in combination housing means; electricallyoperated motormeans in said housing means; means for supplying electrical power tosaid motor means; power-output means operatively connected to saidelectrically operated motor means, said housing means including handlemeans to be gripped in a user''s hand when the tool is operated; switchmeans operatively connected to said motor means for activating anddeactivating the motor means; switch-operator means operativelyconnected to said switch means for operating the tool and normally urgedto an off position; and positively manipulated, switch-operator lockmeans on said handle means operatively connected to said switchoperatormeans and including means for retaining the switchoperator means in anon position and subject to release by momentary reapplication of manualoperator-pressure on said switch operator, said lock means having amanually manipulated operator portion disposed in a recess in saidhandle, and spaced inwardly from the outer surface of said handle, saidoperator portion being accessible to finger engagement by a user,whereby the lock means require positive intentional actuation to bemoved to the position retaining the switch operator means on and isprevented from inadvertent or accidental activation during use oF thetool.
 2. The structure as claimed in claim 1 in which said handle meansdepends from said housing, said switch-operator means comprising atrigger element projecting from said handle means in a convenient,normal position on said handle means whereby said operator means isoperable while conveniently gripped in a user''s hand through a normal,physical gripping action, said switch-operator means being normallyurged toward the off position and being depressible into said handlemeans to turn said tool on, said lock means including spring meansnormally urging it toward a position released from said trigger.
 3. Thestructure as claimed in claim 2 in which said switch-operator meansincludes a portion movable therewith and variably positionable relativeto said means for retaining the switch-operator in an on position,movement lock means comprising a displaceable abutment elementoperatively engaged by said spring means, said displaceable abutmentelement being engagable with said portion movable with saidswitch-operator and operable to prevent the switch-operator from movingto said off position.
 4. The structure as claimed in claim 3 in whichsaid switch-operator means has a path of movement in one direction, saiddisplaceable abutment including a terminal portion positionable in saidpath of mvoement of said switch-operator means portion and engagabletherewith and subject to the force applied to said switch-operatornormally urging it to said off position.
 5. The structure as claimed inclaim 4 in which said switch-operator comprises a finger-engagableportion exposed exteriorly of said handle means, said portion movablewith said switch-operator means comprising at least one recess portion,said abutment portion being displaceably engageable in said recessportion for retaining said switch-operator means in a locked condition.6. The structure as claimed in claim 4 in which said switch-operatormeans includes a recessed portion opening towards said abutment portion,said abutment portion being engagable in said recessed portion forlocking said switch-operator means in a relatively fixed positionsubject to release by manual depression of the switch-operator by theuser of the tool.
 7. A motor housing for a portable, electricallypowered tool including an operator-held handle, switch means in saidhandle including a spring-urged switch-operator element having a portionaccessible exteriorly of said handle for activating said tool, and lockmeans in said handle operatively engageable with said switch-operator,the improvement in which said lock means include an operator elementhaving a portion accessible from outside said handle but spaced inwardlyof the outer surface of said handle, said handle protecting saidoperator element portion from inadvertent actuation whereby a positivephysical manipulation is required to lock the switch-operator in a toolactuating attitude.
 8. The structure as claimed in claim 7 in which saidswitch-operator element includes at least one orienting portion movablerelative to said lock means, said lock means including a spring-urgedabutment element normally urging said lock means to an off position. 9.The structure as claimed in claim 8 in which said switch-operatorcomprises a trigger-like element displaceable in a path of travelrelative to said handle, said orienting portion comprising at least onerecess opening toward said lock means, said lock means comprising anelongated displaceable abutment element retained in a path of movementsubstantially normal to the path of travel of said trigger-like element.10. The structure as claimed in claim 9 in which said lock meanscomprises a sleeve circumposed about and guidingly engaging saidelongated element, spring means circumposed about said elongated elementand normally urging it away from said trigger-like element, the portionexposed at the surface of the handle of said lock means being fixedlyconnected to said elongated element.
 11. The structure as claiMed inclaim 7 in which said handle includes an opening into which an exposedportion of said lock means operator element projects, the outer surfaceof said handle at said opening being spaced outwardly from andprotecting the lock means operator element from inadvertent engagementand actuation by a user''s hand.
 12. The structure as claimed in claim11 in which said handle depends from one end of the housing, theswitch-operator being disposed at an upper inner portion of said handle,said operator element of said lock means being disposed immediatelybelow said switch-operator.
 13. A hand-held, portable, power-operateddevice comprising a housing enclosing a motor, output meansinterconnected with said motor and driven thereby and located exteriorlyof said housing, said housing including a handle portion formanipulation of said device, a motor controlling operator accessiblydisposed on said handle portion for operation by a user, means normallybiasing said operator toward an off position, and lock means for saidmotor controlling operator, said lock means including a fingerengageable portion located in an opening in said handle portion andspaced inwardly from the outer surface thereof, said lock means beingreleasably engageable with said motor controlling operator and operableto lock said operator in said on position, means normally biasing saidlock means toward a position released from said operator, whereby saidlock means and said operator are interconnectable when both are operatoractuated against their respective biasing means, and are releasable topermit said operator to move to its off position upon momentaryreengagement of said operator means by said user.